The present invention relates generally to a housing unit for a heating device.
In order to improve and simplify the design of heating systems, in particular heating devices provided for wall installation, i.e., compact heating systems, such as gas heaters, the prior art typically provides housing units including of one or more injection molded plastic parts. The prior art also provides that the necessary electrical, electronic, hydraulic and mechanical components be integrated therein. The housing units for pure space heating systems here essentially differ structurally from those for heating systems with two heating circuits, in which one is provided for space heating, and another for service water heating. In addition to the always present, at least one recirculation pump, the latter exhibit a heat exchanger, typically a plate heat exchanger, as well as a switching valve or another recirculation pump. In models operating with a switching valve, there are in turn two variants, which specifically have the switching valve in the flow or the switching valve in the return.
For example, a housing unit of the latter type is known from EP 0 918 197 B1. A switching valve is there arranged in the inlet chamber of the pump, wherein the valve body closes or opens the return line of the space heater or return line from the plate heat exchanger, depending on the switch position. The valve body sits on a lever, which is situated roughly vertically in the installed position, and whose other end downwardly exits the housing in a sealing manner, wherein the latter is actuated by means of an electric positioning motor, which is secured to the outside of the housing.
The disadvantage to the housing assembly described in EP 0 918 197 B1 is that the two line ends closed or opened by the valve body are formed by separate injection molded parts, which must only be integrated into the actual housing after its manufacture, which results in added assembly outlay and, given the additional components, added tooling outlay as well. Another disadvantage is that arranging the electric motor on the bottom side of the housing unit impedes the natural line progression, in particular because the return line for the space heater must be rerouted. Therefore, the disadvantage to the housing unit described therein is that it has relatively complex line guides on the inlet side, and the plate heat exchanger can only be laterally shifted and arranged behind the latter, which presents an obstacle to a compact design. The channels running to the plate heat exchanger inside the assembly also require a complicated adapter component to be separately fabricated, which further increases the tooling outlay.